Dawn Smith's adjusted gross income on her Year 1 tax return was $100,000. The amount covered a 12-month period. For the Year 2 tax year, the minimum payments required from Smith to avoid the penalty for the underpayment of estimated tax is:

a. 90% of the current tax on the return for the current year in four equal installments or 100% of the prior years tax liability paid in four equal installments

b. 90% of the current tax on the return for the current year in four equal installments or 110% of the prior years tax liability paid in four equal installments

c. 110% of the prior years tax liability paid in four equal installments only

d. 100% of the prior years tax liability paid in four equal installments only